2 * filter_resample.c -- adjust audio sample frequency
3 * Copyright (C) 2003-2004 Ushodaya Enterprises Limited
4 * Author: Dan Dennedy <dan@dennedy.org>
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software Foundation,
18 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
21 #include <framework/mlt_filter.h>
22 #include <framework/mlt_frame.h>
26 #include <samplerate.h>
27 #define __USE_ISOC99 1
30 #define BUFFER_LEN 20480
31 #define RESAMPLE_TYPE SRC_SINC_FASTEST
36 static int resample_get_audio( mlt_frame frame, int16_t **buffer, mlt_audio_format *format, int *frequency, int *channels, int *samples )
38 // Get the properties of the frame
39 mlt_properties properties = MLT_FRAME_PROPERTIES( frame );
41 // Get the filter service
42 mlt_filter filter = mlt_frame_pop_audio( frame );
44 // Get the filter properties
45 mlt_properties filter_properties = MLT_FILTER_PROPERTIES( filter );
47 // Get the resample information
48 int output_rate = mlt_properties_get_int( filter_properties, "frequency" );
49 SRC_STATE *state = mlt_properties_get_data( filter_properties, "state", NULL );
50 float *input_buffer = mlt_properties_get_data( filter_properties, "input_buffer", NULL );
51 float *output_buffer = mlt_properties_get_data( filter_properties, "output_buffer", NULL );
52 int channels_avail = *channels;
56 // If no resample frequency is specified, default to requested value
57 if ( output_rate == 0 )
58 output_rate = *frequency;
60 // Get the producer's audio
61 mlt_frame_get_audio( frame, buffer, format, frequency, &channels_avail, samples );
63 // Duplicate channels as necessary
64 if ( channels_avail < *channels )
66 int size = *channels * *samples * sizeof( int16_t );
67 int16_t *new_buffer = mlt_pool_alloc( size );
70 // Duplicate the existing channels
71 for ( i = 0; i < *samples; i++ )
73 for ( j = 0; j < *channels; j++ )
75 new_buffer[ ( i * *channels ) + j ] = (*buffer)[ ( i * channels_avail ) + k ];
76 k = ( k + 1 ) % channels_avail;
80 // Update the audio buffer now - destroys the old
81 mlt_properties_set_data( properties, "audio", new_buffer, size, ( mlt_destructor )mlt_pool_release, NULL );
85 else if ( channels_avail == 6 && *channels == 2 )
87 // Nasty hack for ac3 5.1 audio - may be a cause of failure?
88 int size = *channels * *samples * sizeof( int16_t );
89 int16_t *new_buffer = mlt_pool_alloc( size );
91 // Drop all but the first *channels
92 for ( i = 0; i < *samples; i++ )
94 new_buffer[ ( i * *channels ) + 0 ] = (*buffer)[ ( i * channels_avail ) + 2 ];
95 new_buffer[ ( i * *channels ) + 1 ] = (*buffer)[ ( i * channels_avail ) + 3 ];
98 // Update the audio buffer now - destroys the old
99 mlt_properties_set_data( properties, "audio", new_buffer, size, ( mlt_destructor )mlt_pool_release, NULL );
101 *buffer = new_buffer;
104 // Return now if no work to do
105 if ( output_rate != *frequency )
107 float *p = input_buffer;
108 float *end = p + *samples * *channels;
109 int16_t *q = *buffer;
111 // Convert to floating point
113 *p ++ = ( float )( *q ++ ) / 32768.0;
116 data.data_in = input_buffer;
117 data.data_out = output_buffer;
118 data.src_ratio = ( float ) output_rate / ( float ) *frequency;
119 data.input_frames = *samples;
120 data.output_frames = BUFFER_LEN / *channels;
121 data.end_of_input = 0;
122 i = src_process( state, &data );
125 if ( data.output_frames_gen > *samples )
127 *buffer = mlt_pool_realloc( *buffer, data.output_frames_gen * *channels * sizeof( int16_t ) );
128 mlt_properties_set_data( properties, "audio", *buffer, *channels * data.output_frames_gen * 2, mlt_pool_release, NULL );
131 *samples = data.output_frames_gen;
132 *frequency = output_rate;
136 end = p + *samples * *channels;
138 // Convert from floating back to signed 16bit
146 *q ++ = 32767 * *p ++;
148 *q ++ = 32768 * *p ++;
152 fprintf( stderr, "resample_get_audio: %s %d,%d,%d\n", src_strerror( i ), *frequency, *samples, output_rate );
158 /** Filter processing.
161 static mlt_frame filter_process( mlt_filter this, mlt_frame frame )
163 if ( mlt_frame_is_test_audio( frame ) == 0 )
165 mlt_frame_push_audio( frame, this );
166 mlt_frame_push_audio( frame, resample_get_audio );
172 /** Constructor for the filter.
175 mlt_filter filter_resample_init( mlt_profile profile, mlt_service_type type, const char *id, char *arg )
177 mlt_filter this = mlt_filter_new( );
181 SRC_STATE *state = src_new( RESAMPLE_TYPE, 2 /* channels */, &error );
184 void *input_buffer = mlt_pool_alloc( BUFFER_LEN );
185 void *output_buffer = mlt_pool_alloc( BUFFER_LEN );
186 this->process = filter_process;
188 mlt_properties_set_int( MLT_FILTER_PROPERTIES( this ), "frequency", atoi( arg ) );
189 mlt_properties_set_int( MLT_FILTER_PROPERTIES( this ), "channels", 2 );
190 mlt_properties_set_data( MLT_FILTER_PROPERTIES( this ), "state", state, 0, (mlt_destructor)src_delete, NULL );
191 mlt_properties_set_data( MLT_FILTER_PROPERTIES( this ), "input_buffer", input_buffer, BUFFER_LEN, mlt_pool_release, NULL );
192 mlt_properties_set_data( MLT_FILTER_PROPERTIES( this ), "output_buffer", output_buffer, BUFFER_LEN, mlt_pool_release, NULL );
196 fprintf( stderr, "filter_resample_init: %s\n", src_strerror( error ) );